JPH1029890A - Backup mechanism for crystal pulling-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly restart a pulling-up operation at the time of rising of a power source again by supplying electric power for emergency to the respective parts of a pulling-up device in the event of a service interruption. SOLUTION: This mechanism backs up the electric power consuming apparatus of the crystal pulling-up device for pulling up the crystal from the melt in a melt-housing crucible arranged in a vacuum vessel. In such a case, a computer for controlling the pulling-up machine is segmented to a group A. A heater for heating the crucible, a heater for heating the crucible, motor for rotating the vacuum pump and the crucible, motor for rotating the crystal, magnetic field impressing device, solenoid valve, crucible moving motor, crystal moving motor and other electric power consuming apparatus are segmented to a group B. The electric power consuming apparatus of the group A are connected via an uninterruptible power supply to a commercial power supply. The circuits connecting the electric power consuming apparatus of the group B and the commercial power source are provided with a switch having terminals arriving at a generator in the mid-way thereof and the electric power consuming apparatus of the group B are connected to the uninterruptible power supply via a normally open switch. In case of the service interruption of the commercial power supply, the electric power is supplied from the uninterruptible power supply to the apparatus of the group A and the generator is excited. The electric power is then supplied from the generator to the apparatus of the group B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backup mechanism for a crystal pulling apparatus which suppresses the occurrence of a trouble at the time of a power failure and allows a high-quality single crystal to be pulled without trouble even after restarting a commercial power supply. .

[0002]

2. Description of the Related Art In growing a single crystal by the Czochralski method, an apparatus having an equipment configuration as shown in FIG. 1 is used. The melt 1 is accommodated in a quartz crucible 2 and set in a vacuum vessel 3 held in an Ar atmosphere. The melt 1 is heated by a heater 4 circulating around a quartz crucible 2 and is maintained at a high temperature with a predetermined temperature gradient in the vertical direction. A heat insulating material 5 is arranged on the outer periphery of the heater 4 so that the retained heat of the melt 1 does not dissipate. In FIG. 1, the resistance heating system in which the heater 4 is energized from the electrode 6 is employed, but the melt 1 can be maintained at a high temperature by high frequency heating. Melt 1 with controlled temperature
The seed crystal 8 supported by the holder 7 is brought into contact with the melt 1
To grow a single crystal 9. The single crystal 9 is pulled up according to the degree of growth. During the pulling, the quartz crucible 2 and the single crystal 9 are rotated in directions opposite to each other, and the growth conditions are controlled while measuring the diameter of the single crystal 9 with the detector 10.

In this pulling apparatus, power consuming devices such as a pulling machine control computer, a crucible moving motor, a crystal moving motor, a crucible heating heater, a vacuum pump, a crucible rotating motor, a crystal rotating motor, and an electromagnetic valve are used. I have. Further, in the MCZ method having a function of controlling the convection of the melt, power is consumed even by a power supply for a superconducting magnet for generating a strong magnetic field. As a power source, a commercial power supply is usually used, but the commercial power supply may lose power due to lightning strikes, interference by animals, and the like. Trouble caused by a power failure can be prevented by attaching a storage battery as an uninterruptible power supply. According to the conventional method, the commercial power is supplied to the commercial power and a computer for controlling the pulling machine, a crucible moving motor, and a crystal moving motor (hereinafter referred to as group A) through an uninterruptible power supply as shown in FIG. I have. Also,
Heaters, vacuum pumps,
There is also a system for supplying commercial power to devices such as a magnetic field applying device and a solenoid valve (hereinafter referred to as “Otsu group”).

When the commercial power supply is interrupted, the information stored in the memory to keep track of the status of the equipment during the process is directly stored in the computer for controlling the hoisting machine by the electric power discharged from the storage battery of the uninterruptible power supply. The crystal is held, and is brought into a standby posture for resuming the crystal pulling after the energization. At this time, since the crucible drive motor is backed up, the graphite crucible surrounding the quartz crucible and the heater 4 are prevented from being broken by the solidification and expansion of the melt 1 generated after the power failure. Also, the fact that the grown crystal 9 is in contact with the melt 1 and is confined simultaneously with the solidification of the melt 1
This is prevented by backing up the crystal drive motor so that the crystal 9 is separated from the melt 1 at the time of power failure.

[0005]

However, the conventional power failure countermeasures do not back up all the power supplies of the pulling machine, so that various troubles occur due to the stoppage of the driving of each part. For example, with regard to the electronic equipment of the group B, the power consumption is several hundred KW and cannot be backed up. For this reason, once a power failure occurs, the melt solidifies or adheres to the inside of the furnace due to insufficient exhaustion of SiO. Even if crystal growth is resumed after re-energization, the yield is significantly reduced. In particular, the vacuum pump may be stopped at the moment when the power is turned off. When the operation of the vacuum pump is stopped, the SiO evaporated from the melt 1 is not discharged to the outside of the vacuum vessel 3 and adheres to the inner wall of the vacuum vessel 3 and internal equipment. The attached SiO drops into the melt 1 when the single crystal pulling is restarted after the power is turned on again, and causes dislocation in the grown single crystal 9. As a result, the yield of a single crystal as a product is significantly reduced.

If the power failure continues for a long time, the melt 1 contained in the quartz crucible 2 may solidify. When the melt 1 is solidified, the pulling operation of the single crystal 9 cannot be continued, and not only the product yield decreases, but also there is a possibility that the graphite crucible surrounding the quartz crucible 2 and parts in the furnace may be damaged. In particular, in recent years in which the scale of the pulling apparatus tends to be large, the adverse effects of such troubles cannot be ignored. The present invention has been devised to solve such a problem.A storage battery and a generator are attached via an uninterruptible switch, and emergency power is supplied to each part of the pull-up device at the time of a power failure, and the power is again supplied. The purpose of the present invention is to smoothly resume the pulling operation when the power supply is turned on.

[0007]

SUMMARY OF THE INVENTION In order to achieve the object, a backup mechanism for a crystal pulling apparatus according to the present invention is a crystal pulling apparatus for pulling a crystal from a melt contained in a melt accommodating crucible disposed in a vacuum vessel. A mechanism that backs up power consumption equipment, with a computer for pulling machine control as a group, a vacuum pump, a crucible rotating motor, a crystal rotating motor, a crucible moving motor, a crystal moving motor, a crucible heating heater, a magnetic field applying device, and an electromagnetic valve. And the other power consuming devices are classified into group B, and the power consuming devices in group A are connected to the commercial power source via uninterruptible power supply, and power is generated in the middle of the line connecting the power consuming devices in group B and the commercial power source. A switch having terminals to the machine is provided, and a group of power consuming equipment is connected to the uninterruptible power supply via a normally open switch.

It is preferable that a lightning detector is connected to the generator in an interlocking manner, and the generator is started to be driven by a signal from the lightning detector that detects the approach of lightning. The uninterruptible power supply supplies current to the control unit of the crystal pulling device without interruption, stores the information before the power failure in the control unit, a power failure detection circuit that detects the power failure state of the commercial power supply, and uninterrupted commercial power supply in the event of a power failure. Equipped with an uninterruptible switching device that switches to the power supply. In the event of a power outage, the uninterruptible power switch is switched to supply power from the storage battery to a group of power consuming equipment, and a start signal is supplied to the generator to start the generator. Power is supplied to the power consuming equipment of the group and the group B, and the uninterruptible switching device is switched again after the commercial power is reconnected, and the power is supplied from the commercial power to the power consuming equipment of the group A and the group B.

[0009]

FIG. 3 shows a crystal pulling apparatus according to the present invention.
As shown in the figure, the computer for the hoisting machine control, which consumes relatively little electric power, is the first group, and the heater, vacuum pump, crucible rotating motor, crystal rotating motor, crucible moving motor, crystal moving motor, magnetic field applying device, which consume a large amount of power, , Solenoid valves and other power consuming equipment. Kabutogun storage battery through the normally open switch SW _2, a power failure detection circuit,
It is connected to an uninterruptible power supply provided with an uninterruptible switch, and the uninterruptible power supply is connected to a commercial power supply. As such an uninterruptible power supply, a known power supply is used. Party B group is connected to a commercial power source via a switch SW _1,
A generator equipped with a lightning detector is installed on the way. Switch SW ₁ is provided with a terminal B of the terminal A and the generator side of the commercial power supply side. Normally open switch SW ₂ is provided on the output side of the uninterruptible power supply is enabled to open and close the current from the generator at terminal C. Although not shown, a current backflow prevention mechanism that functions during operation of the generator is provided inside the uninterruptible power supply.

[0010] In the steady state, the switch SW _1, as shown in FIG. 3 are connected to the terminal A, the power to the equipment of Party B group from the commercial power supply is supplied. Further, a terminal C of the normally open switch SW ₂ is opened, power is supplied through the uninterruptible power from a commercial power source for MIG group devices. At this time,
The towing machine control computer not only controls each device, but also always stores the state of each device in real time in a memory. Thereby, even if a power failure occurs, the program is programmed so that each device can immediately return to the state before the power failure when the power is restored. When the lightning approaches, the approaching lightning is detected by the lightning detector, and the lightning detector outputs an operation signal to the generator. The generator automatically starts operating upon receiving the operation signal. At this time, the switch S
W ₁ is switched to the terminal B as shown in FIG. 4 from the steady state of FIG. Further, normally open switch SW ₂ is connected to the terminal C. The current generated by the generator is adjusted so that the waveform of the AC frequency coincides with the current from the commercial power supply, and is supplied to various devices of the first and second groups. Incidentally, the uninterruptible power supply current from the generator is provided with a current backflow preventer so as not to flow back to the commercial power source via a normally open switch SW ₂ and uninterruptible power. Because this state is maintained when lightning approaches,
The towing machine is constantly operated by the current from the generator even when the commercial power supply is interrupted.

When the danger of a power failure disappears as the lightning strikes, the switches SW ₁ and SW ₂ return to the steady state shown in FIG. Then, the current source is changed from the generator to the commercial power supply, and the pulling machine is operated without interruption. In addition, even when the commercial power supply actually fails, the current is supplied from the generator, so the state shown in Fig. 4 is maintained even after the commercial power supply is restored, and the current from the generator is Equipment. Commercial power in this state is sure to allow suitable time stabilized, to return the switch SW ₁ and SW ₂ in the steady state of FIG. As a result, the generator is switched to the commercial power supply without stopping the operation of the pulling machine, and the crystal growth can be continued.

As described above, in the backup mechanism according to the present invention, the power consuming devices are divided into the first group and the second group. Comparing this section with the case of FIG. 2 without a generator, the difference is that the crucible moving motor and the crystal moving motor are moved to the group B and backed up by the generator. That is, the generator is not always running, but is activated in advance when it is determined that the commercial power supply is likely to be out of power, and prepares for the power outage. For example, a sudden power outage may occur when animals interfere with commercial power, but it is extremely expensive to keep the generator running at all times in anticipation of such a situation. Should be replaced with a commercial power supply and used as a power supply. However, even in a method using a private power generator as a power source, it is required to provide a backup generator in a method according to the present invention, so that an infinite chain is generated and any generator cannot be backed up.

On the other hand, in the method proposed in the present invention,
In the event of a sudden power outage, the computer monitors the status of the key parts of the hoist before the power outage without interruption, and prepares to resume the operation of the hoist after the generator is running.
Specifically, even if the generator starts to operate automatically or manually after a sudden power failure, power can be transmitted to the power consuming devices of the first and second groups in about 15 seconds. On the other hand, if a generator is not provided, it is required that the commercial power supply source be assured that the time required for the commercial power supply to recover after a sudden power outage can be about 20 minutes so that the molten material of the puller does not solidify. . However, the spread of sudden power outages can take several hours or more,
Such a promise cannot be guaranteed.

In this respect, according to the present invention, since power can be transmitted to the group B in a short time and reliably by the in-house generator, the crucible movement and the crystal movement are completed before the solidification of the melted raw material is completed. Therefore, it is possible to prevent the graphite portion from being damaged due to the expansion of the crucible accompanying the solidification of the molten raw material, and the grown crystal from becoming unusable due to the pulled crystal being adhered to the solidified portion of the molten raw material. Can be Further, it is possible to prevent the molten raw material from leaking from the remaining portion of the molten raw material due to the crystal falling and causing a steam explosion. In addition, since the moving motors for the crucible and the crystal are divided into the group B, the power load of the uninterruptible power supply is reduced to about 100 W only for the backup of the computer. In this regard, the power load when backing up all power consuming equipment is several kW, and when comparing with the need for an uninterruptible power supply that can withstand this power load, The significance of separate backup is clear.

[0015]

As described above, in the present invention, even when a power failure occurs, the power from the storage battery is used, so that various devices do not immediately stop driving, and a sudden change in the pulling atmosphere can be avoided. . Since the power obtained by the generator that starts up during a power outage can be used for backup of various devices, the yield of single crystal products is not significantly reduced, and damage to internal devices is also prevented. Therefore, it becomes possible to operate a particularly large-scale pulling apparatus with high productivity.

[Brief description of the drawings]

Fig. 1 Crystal pulling device by Czochralski method

Fig. 2 Conventional power supply system with backup

FIG. 3 shows a power supply system with backup according to the invention

FIG. 4 is a power supply system when a commercial power supply is in a power failure state

[Explanation of symbols]

1: Melt 2: Quartz crucible 3: Vacuum container 4:
The heater 5: heat insulating material 6: electrode 7: Holder 8: Seed crystal 9: monocrystalline 10: Detector SW _1: switch with terminal leading to the generator SW _2:
Normally open switches A to C: Terminal

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kiyotaka Takano 1-4-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Norimitsu Takase 1-4-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Tetsuhiro Iida Tokyo 1-4-2 Marunouchi, Chiyoda-ku (72) Inventor Junichi Matsubara 1-4-2 Marunouchi, Chiyoda-ku, Tokyo

Claims (3)

[Claims] A mechanism for backing up a power consumption device of a crystal pulling apparatus for pulling a crystal from a melt contained in a melt containing crucible disposed in a vacuum vessel, comprising a computer for controlling the puller, a vacuum pump, , Crucible rotating motor, crystal rotating motor, crucible moving motor, crystal moving motor, crucible heating heater, magnetic field applying device, solenoid valve and other power consuming equipment A power consuming device is connected to a commercial power source, and a switch having a terminal to a generator is provided in the middle of a line connecting the power consuming device of the group B and the commercial power source, and the power consuming device of the group B is connected via a normally open switch. And a backup mechanism for the crystal pulling device connected to the uninterruptible power supply. 2. A backup mechanism for a crystal pulling device according to claim 1, wherein a lightning detector is interlocked to the generator, and driving of the generator is started by a signal from the lightning detector that detects the approach of lightning. . 3. An uninterruptible power supply supplies a current to the control unit of the crystal pulling apparatus without interruption, stores a storage battery for storing information before the power failure in the control unit, a power failure detection circuit for detecting a power failure state of the commercial power supply, and a power failure detection circuit. Equipped with an uninterruptible power switch that switches the commercial power supply to the uninterruptible power supply, switches the uninterruptible power switch during a power outage, supplies power from the storage battery to the group B power consumers, and supplies a start signal to the generator. Start the generator, then close the normally open switch to supply power from the generator to the power consuming equipment of Party A and Party B, switch the uninterruptible switch again after the commercial power is reconnected, and switch The backup mechanism for a crystal pulling apparatus according to claim 1, which supplies power to a group of power consuming equipment.